1. Field of the Invention
This invention relates to the field of pumps and more particularly to a pump with an enhanced high-pressure seal.
2. Description of the Related Art
High pressure pumps are used in many applications including hydraulic systems, pressure washers and presses. A high-pressure pump is described in U.S. Pat. No. 6,092,370 to Tremoulet, Jr. et al., issued on Jul. 25, 2000 and is hereby incorporated by reference in its entirety.
Often, high pressure pumps are used in applications where leaks are a problem. For example, a leaking pump in an airplane may cause the loss of hydraulic fluid. Furthermore, the lost fluid may create an environmental issue or, at least, may create a stain or a slippery area that may contribute to falling or slipping danger.
One problem area in high pressure pumps is the high pressure seal which helps keep pressurize fluids inside the pump. At high pressures, some exceeding 100,000 psi, high pressure seals often fail. It is believed that leaking of the high pressure seal may be the most common problems in high pressure pumps. The failure usually begins with a slow leak, wherein the pump is fully functional and only a small amount of fluid is lost. Furthermore, beyond a slight loss in output pressure, leaks from the high pressure seal can also impact other parts of the pump through loss of lubrication, fatigue and corrosion.
This problem is known in the industry and has been addressed by many solutions including placing a higher, more even force on the seal. For example, US Publication 2005/0074350A1 to Raghavan, et al., published Apr. 7, 2005, describes a “Device and Method for Maintaining a Static Seal of a High Pressure Pump,” and is hereby incorporated by reference. A pump is described in U.S. Pat. No. 3,966,360 to Greene, issued Jun. 29, 1976. This pump has an outer casing forming a reservoir. Such solutions may improve the performance of such seals, but they do not prevent the problem and, when a seal leaks, the loss of fluid or the resulting spill may cause problems.
What is needed is a pump with a high pressure seal in which any leaking in the high pressure seal feed back into the input chamber of the pump.